Drive mechanism for imaging apparatus

ABSTRACT

An electrical-mechanical drive mechanism is employed in a photoelectrophoretic imaging system to propel a flat plate electrode on which images are formed along a generally linear path and to rotate roller electrodes that contact the flat plate during its travel. The angular speed of the rollers and the translational speed of the flat plate are synchronized to minimize disturbing an image on the flat plate electrode. Separate drive mechanisms rotate the rollers prior to the arrival of the flat plate adjacent a roller to overcome inertia of the roller and to perform operations secondary to the imaging process.

United States Patent [72] Inventors Raymond K. Egnaczak Williamson;Charles H. Myers, Palmyra, both of NY.

21 1 Appl. N0. 876,636

[22] Filed Nov. 14, 1969 [45] Patented Nov. 30, 1971 [73] Assignee XeroxCorporation Rochester, N.Y.

[ 54] DRIVE MECHANISM FOR IMAGING APPARATUS 16 Claims, 34 Drawing Figs.

[52 us. Cl 355/3,

232, 233. 234, 235; 355/3, 84 [56] References Cited UNITED STATESPATENTS 2,854,920 10/1958 Frankle et a1 1/1969 Grobman et a1.

3,422,757 101/232 3,427,242 2/1969 Mihajlov 355/3 UX 3,486,819 12/1969Di Giulio 355/8 X 3,397,628 8/1968 Granzow et a1 355/8 PrimaryExaminer-Samuel 8. Matthews Assistant E.\'aminer Kenneth C. HutchisonAllorneys.lames J. Ralabate, David C Petre and Michael H.

Shanahan ABSTRACT: An electrical-mechanical drive mechanism is employedin a photoelectrophoretic imaging system to propel a flat plateelectrode on which images are formed along a generally linear path andto rotate roller electrodes that conrollers and the translational speedof the flat plate are synchronized to minimize disturbing an image onthe flat plate electrode. Separate drive mechanisms rotate the rollersprior to the arrival of the flat plate adjacent a roller to overcomeinertia of the roller and to perform operations secondary to the imagingprocess.

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1. A drive mechanism comprising main drive means for propelling a platemember back and forth along a generally linear path past a first rollerwith which it makes contact, first auxiliary drive means for rotatingthe first roller, and clutch means for alternately coupling the firstroller to the main and auxiliary drive means to have the first rollerrotated by the main drive means when the plate member and first rollerare in contact at an angular velocity directly related to the linearvelocity of the plate and to have the first roller rotated by theauxiliary drive means when the plate and first roller are not incontact.
 2. The mechanism of claim 1 wherein said auxiliary drive meansincludes means to rotate said first roller at an angular velocitysubstantially the same as the velocity produced by said main drive meansto minimize the load exerted on the main drive means when the clutchmeans couples the first roller to the main drive means.
 3. The mechanismof claim 1 further including a second roller positioned adjacent thefirst roller and making contact with the plate member as it travelsthereby, and second auxiliary drive means for rotating said secondroller and wherein said clutch means includes means for alternatelycoupling said second roller to said second auxiliary and main drivemeans to have the second roller rotated by the main drive means when thesecond roller and plate member are in contact at an angular velocitydirectly related to the linear velocity of the plate member and to havethe second roller rotated by the second auxiliary drive means when thesecond roller and plate member are not in contact.
 4. The apparatus ofclaim 1 wherein said main drive means includes a first continuous beltmember rotated clockwise and counterclockwise by a first motor coupledthereto and having means for reversing its direction of rotation.
 5. Theapparatus of claim 4 wherein said first auxiliary drive means includes asecond continuous belt member rotated clockwise and counterclockwise bya second motor coupled thereto and having means for reversing itsdirection of rotation.
 6. The apparatus of claim 5 wherein said clutchmeans includes main clutch means for coupling said first continuous beltmember to said first roller and auxiliary clutch means for coupling saidsecond continuous belt member to said first roller.
 7. The apparatus ofclaim 6 further including switch means actuated as said plate membertravels thereby to engage said main clutch means when the plate andfirst roller are in contact and to engage said auxiliary clutch meanswhen the plate and said first roller are not in contact.
 8. Themechanism of claim 1 wherein said clutch means includessolenoid-operated main clutch means coupled to the main drive means andthe first roller for transmitting power thereto when a first solenoid isenergized, solenoid-operated auxiliary clutch means coupled to theauxiliary drive means and the first roller for transmitting powerthereto when a second solenoid is energized, first cam-operated switchmeans to prevent the simultaneous application of power to the firstroller member by the main and auxiliary drive means having a firstswitch position to energize said first solenoid when the plate membercontacts the first roller and a second switch position to energize saidsecond solenoid when the plate Member is not in contact with the rollermember.
 9. The mechanism of claim 1 further including inking means toapply a fluid to the surface of said roller as it is rotated by theauxiliary drive means to coat the surface of the roller with said fluidbefore the plate member contacts the first roller.
 10. The mechanism ofclaim 9 wherein said fluid is a photoelectrophoretic ink and furtherincluding means for coupling the plate member and first roller to avoltage source to establish an electric field across ink between theplate member and roller and exposure means for exposing the ink betweenthe plate member and roller to electromagnetic radiation to form animage on the plate member from ink subjected to electric field andexposed to radiation.
 11. The mechanism of claim 10 wherein said firstroller is rotated by said main drive means at an angular velocity suchthat a point on the periphery of the roller has substantially the samevelocity as a point on the platen.
 12. The mechanism of claim 9 furtherincluding elevator means for moving the first roller generallyperpendicular to the path of said plate member when activated, to enablethe first roller to contact the plate member as it travels thereby. 13.The mechanism of claim 12 further including second cam-operated switchmeans thrown to a first position as the plate member approaches thefirst roller to activate said elevator means and thrown to a secondswitch position as the plate member clears the first roller todeactivate said elevator means.
 14. The mechanism of claim 1 furtherincluding first and second spray means for spraying a fluid onto thesurface of said first roller, when activated, at least when it is incontact with the plate member, and third cam-operated switch meansthrown to a first switch position to activate said first spray means asthe plate member passes the first roller from right to left and thrownto a second switch position to activate the second spray means as theplate member passes the first roller from left to right.
 15. Themechanism of claim 1 further including a second roller coupled to saidmain drive means by an auxiliary clutch means and positioned to compressa web against the plate member as it travels thereby causing the web tobe advanced with said plate member, and web feed means for dispensingsaid web from a spool when the web is advanced with said plate member.16. The mechanism of claim 15 further including elevator means formoving said second roller generally perpendicular to the path of saidplate member, when activated, to compress the web against the platemember as it travels thereby, and fourth cam-operated switch means toactivate said elevator means as said plate member approaches the secondroller.